U.S. President Donald Trump warned on Tuesday he might terminate the NAFTA trade treaty with Mexico and Canada after three-way talks failed to bridge deep differences.

The United States, Canada and Mexico wrapped up their first round of talks on Sunday to revamp the trade pact with little sign of a breakthrough coming. Trump reopened negotiations of the 1994 treaty out of concern U.S. economic interests were suffering.

“Personally, I don’t think we can make a deal. I think we’ll probably end up terminating NAFTA at some point,” Trump said at a political rally in Phoenix, Arizona.

Suggesting a termination might help jumpstart the negotiations, Trump said: “I personally don’t think you can make a deal without a termination.”

Following Trump’s remarks, Mexican foreign minister Luis Videgaray tweeted: “No surprises: we’re already in a negotiation. Mexico will remain at the table with serenity, firmness and with the national interest ahead.”

In a joint statement issued at the end of five days of negotiations in Washington, the top trade officials from the three countries said Mexico would host the next round of talks from Sept. 1 to 5.

The talks will move to Canada later in September, then return to the United States in October, with additional rounds planned for later this year.

(Reporting by Steve Holland in Washington and Dave Graham in Mexico City; Editing by Nick Macfie)